ANSWER: A The criteria for acute T-cell mediated rejection Banff grade IA includes interstitial inflammation involving >25% of non-sclerotic cortical parenchyma (i2 or i3) with moderate tubulitis (t2) involving 1 or more tubules, not including tubules that are severely atrophic.
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True! Histologic evidence of acute tissue injury in AABMR includes 1 or more of the following: microvascular inflammation (glomerulitis and/or peritubular capillaritis), intimal or transmural arteritis, and acute TMA and acute tubular injury (in the absence of any other apparent cause)
This allograft biopsy shows the characteristic features of adenovirus infection. There is prominent interstitial hemorrhage and edema (Fig. 1), acute tubular injury with viral cytopathic effect and positive immunohistochemical cytoplasmic and nuclear staining for adenoviral antigen (Fig. 2), and foci of tubular necrosis (Fig. 3). The differential diagnosis for this morphology in the transplant setting includes other viral infection (e.g. polyomavirus, CMV, HSV), acute rejection, and drug-related acute interstitial nephritis.
A diagnosis of chronic active antibody-mediated rejection (ABMR) requires morphologic evidence of chronic tissue injury (e.g. transplant glomerulopathy), evidence of current or recent antibody interaction with the vascular endothelium (e.g. linear C4d staining of peritubular capillaries), and serologic evidence of donor specific antibody (DSA) formation. Importantly, the revised 2017 Banff classification of ABMR and T cell-mediated rejection (TCMR) recognizes C4d positivity as a substitute for DSA for diagnosing ABMR, although DSA testing is still strongly encouraged (see reference). The images are from a patient with an elevated serum creatinine who had undergone living unrelated kidney transplant four years ago. The...
ANSWER: C Mild to moderate intimal arteritis (v1), with or without interstitial inflammation and/or tubulitis is considered as acute TCMR Grade IIA based on the Banff 2017 classification. Importantly, arterial lesions (v>0) may be indicative of ABMR, TCMR or mixed ABMR/TCMR.
ANSWER: B The criteria for acute T-cell mediated rejection Banff grade IB includes interstitial inflammation involving >25% of non-sclerotic cortical parenchyma (i2 or i3) with severe tubulitis (t3) involving 1 or more tubules, not including tubules that are severely atrophic.
Chronic active T cell-mediated rejection (TCMR) was included in the 2017 Banff classification system for the evaluation of kidney allografts (see reference). This diagnosis recognizes the usually deleterious effects of interstitial inflammation on graft survival, even within areas of interstitial fibrosis and tubular atrophy (IFTA). The biopsy shows severe chronic inflammation (Fig. 1) in the setting of moderate to severe IFTA (Fig. 2), as well as foci of severe tubulitis in non-atrophic tubules (Fig. 3). Haas M, Loupy A, et al. Am J Transplant. 2018 Feb;18(2):293-307. PubMed PMID: 29243394
What is your diagnosis in this renal transplant biopsy? ...
This biopsy was performed on an 81-year-male, status post renal transplant, who presented with increased creatinine (2.3 mg/dl) and microscopic hematuria. Light microscopic examination of the biopsy shows diffuse mesangial and mild endocapillary hypercellularity with rare double contour formation of the capillary loops (Fig 1 and 2). No significant tubulointerstitial inflammation, peritubular capillaritis or endothelialitis is present, to otherwise suggest and underlying component of acute T-cell or antibody mediated rejection. Immunofluorescence (Fig 3) shows mesangial and segmental capillary loop positive staining for IgG (3+), C3 (3+), C1q (1+) and lambda light chain (3+). All other stains, including kappa light chain...
ANSWER: C Intimal arteritis (v1 and v2) is more commonly associated with mixed ABMR/TCMR than with “pure” ABMR. It may also be seen in TCMR in absence of DSAs. In ABMR, intimal arteritis is associated with a poorer prognosis.